Synthetic sapphire.



' A. V. L. VERNEUIL.

SYNTHETIC SAPPHIRE.

APPLIOATION FILED JUNE 28. 1911.-

Patented Sept. 26, 1911.

UNiTED STATES PATENT OFFICE.

AUGUSTE VICTOR LOUIS VERNEUIL, OF PARIS, FRANCE, ASSIGNOR TO L. HELLER &SON, OF NEW YORK, N. Y.

SYNTHETIC SAPPHIRE.

Specification of Letters Patent.

Application filed June 28, 1911.

Patented Sept. 26, 1911.

Serial No. 635,753.

synthetically stones having a hardness,v

color, chemical composition and other physical characteristics asclosely resembling the natural sapphire as possible.

As is well known, artificial rubies have already been manufacturedsynthetically,

but prior to my present invention it has been impossible tosynthetically produce a sapphire with the true hardness and true colorof the natural sapphire, and therefore it has not been heretoforepossible to use synthetic sapphires both in the arts and for gems as isnow the case.

Therefore, this invention consists in a synthetic sapphire which may beproduced in accordance with the disclosure found in my Patent No.988,230, dated March 28, 1911, which having the same hardness and coloras natural sapphires, is useful as an abradent, for other mechanicalpurposes, as well as being useful as a gem, and which although it iscapable of being distinguished from the natural sapphire, it yetpossesses the same chemical composition and almost all other physicalcharacteristics, as will be more fully disclosed hereinafter.

Referring to the accompanying drawings forming a part of thisspecification in which like characters designate like parts in all theviews and in which an apparatus suitable for carrying out this inventionis illustrated:-Figure 1 is a diagrammatic view of one form of apparatusused, and Figs. 2 to 6 show the artificial sapphire at different stagesof the process.

Oxy en islet from a suitable source throug the pipe 0 into the chamberA, which latter contains a receptacle B for the powder, afterward fusedinto the artificial sapphire. The lower end of this receptacle Bterminates in a sieve-like portion B, composed of wire gauze or similarmaterial and 6.

of sufiiciently fine mesh to prevent the powder from falling freelytherethrough. The upper end of the receptacle B has attached to it arod, passing through an air-tight joint in the top of the chamber A, andprovided at its upper end with a block 0. The block C is placed withinreach of a hammer D fixed to a rod E, which is pivotally mounted at F.The end of the rod E opposite to the hammer D is adapted to beperiodically depressed by the cam G on the shaft J, which shaft rotatesin the direction of the arrow. As the cam G strikes the end of the rodE, the hammer D is raised and when the cam, in its rotation, isdisengaged from the rod E, the hammer falls and 1mparts a shock to thesieve-like portion B through the block C and the connecting rod. In thisway, a small quantity of the powder is delivered at intervals throughthe opening in the lower part of the chamber A and through the pipe K.The illuminating gas or'other suitable fuel is fed through the openingH, passes down through the pipe S, and at the mouth of the latterminglcs with the oxygen to form the flame which is inclosed by a casingM of a refractory substance. Inside of the casing M, is a fire claycolumn L, which may be adjusted by means of the bent rod N, bracket Q,screwthreaded rod R, and handles P and T.

At the beginning of the process, the oxygen is only fed in smallquantities, so that the flame 1s, relatively speaking, cool. The powderfalling through the flame onto-the fire clay column or support L isaccordingly not fused, but merely baked or fritted, and gradually formsa cone 1 of the shape shown inFig. 2. As the cone increases 1n size, theflame acts directly on the point of the cone, which, being a very smallmass, is fused and the powder blown in by the flame passesinstantaneously to the crystalline state at the moment of fusion,forming a small stalk 2 of the crystalline formation, as shown in Fig.3. The proportion of oxygen in the flame is then gradually increased andthe owder fallin down fuses and forms a bu of gradually increasing size,as shown at 3, 4, and 5 in Figs. 4, 5, The cone when started is a balland grows in curved layers by the additions of material. Curved linesdue to these layers are often visible to the naked eye in the cutstones. Natural stones do not appear to be formed in this way, sincethey often disclose straight parallel lines or layers. When,the cone iscompleted the flame is then shut off and the artificial stone allowed tocool. The reactions, so far as I have been able to determine them are asfollows: As these substances, mixed together and in a powderedcondition, fall through the flame, the reaction first consists in thereduction of the oxid of iron to a lower oxid, and then in thesimultaneous oxidation of the lower oxid of iron to the sesquioxid(Fe,O,) and the reduction of the oxid of titanium to a lower oxid. Theblue color of the stone thus ultimately obtained is probably due to thelower oxid of titanium, and the function'of the oxid of iron is that ofa reducing agent.

When the cone 1, shown in Fig. 2, is formed, the mixture of alumina andthe above oxids of iron and titanium then fuses and the artificialsapphire forms gradually, as described above and shown'in Figs. 2 to 6.The proportions of the powdered ingredient-s are substantially 98 percent. alumina, 1.5 per cent. ferrous oxid of iron, and 0.5 per cent.oxid of titanium. But in making these stones a somewhat largerpercentage of iron oxid is used than chemical analysis shows to exist inthe finished product. It is therefore believed since the oxid of ironhas a lower melting point than corundum, that the excess escapes in agaseous condition and causes the round shaped bubbles which may beobserved, embedded in the body of the synthetic sapphire, if a propermagnifying glass is used, or sometimes even with the unaided eye. Inaddition to the above, 00- rundum does not become viscous or pasty likeglass, and as the flame is at a temperature above its melting point, thestone during its formation at one point. or another contains corundum ina gaseous state, and it is believed the finer bubbles observed in theproduct may be due to this cause.

Other compounds of aluminum-, iron and titanium could be usedtoconstitute the ingredients of the powder'besides the oxids abovementioned, owing to the fact that the flame, whose temperature duringthe formation of the stones should be kept at about 1900 0., wouldreduce any other compounds of these metals which might be used to thestate of oxids during their passage through the flame, as at thistemperature none of the compounds of these metals are stable, except theoxids. If other compounds of these metals are used, however, theproportions in which they enter into the composition of the powder mustobviously be corres ondingly changed to give the final proportions abovementioned. It should be understood that it is not absolutely necessaryto combine the powdered alumina with the powdered oxids of titanium andiron, which are the cutting operation.

prepared in the usual manner. One could start with the sulphates,carbonates, or other compounds, or even the pure powdered-metals couldbe used, provided as already stated, that the proportions arecorrespondingly varied.

The sapphires produced by the above method and means have a hardness of9, diamond being 10, and may be distinguished on the market from thenatural sapphires by observing the following differences in theirphysical characterist1cs:Cracks or scratches are often seen in thenatural stones under a high power microscope, but they seem to be on thesurface and resemble the parallel scratches made by a file on the edgeof a glass plate. They are probably due to In the synthetic stone, onthe other hand, the cracks when they occur, appear as genuine riftsbeneath the surface, and are generally curved, due probably to thecurved layers out of which the stone is formed. The layers comprisingthe natural stone are flat and parallel, while those of the syntheticstone are curved, as above stated. The specks or cavity like spotsappearing in the natural stone are bounded by angular or crystal shapedwalls, while those occurring in the synthetic stone have curved orbubble like walls. 'The above characteristics in nearly all cases mustbe a cost enabling them to be used either as gems, or in the variousmechanic arts, and therefore, I do not wish to be limited to anyparticular use.

What Iclaim is 1. synthetic sapphire containing aluminum, lron andtitanium, having beneath its surfaces bubble like spots bounded withrounded walls, substantially as described.

2. A synthetic sapphire containing aluminum, iron and titanium, andhaving beneath its surfaces bubble like spots bounded with roundedwalls, and also curved rift like streaks or cracks, substantially asdescribed.

3. synthetic sapphire containing aluminum, iron and titanium of a bluishcolor, having a hardness of substantially 9,- diamond being 10, andhaving beneath its surfaces bubble like spots bounded with roundedwalls, substantially as described.

4. cut and finished synthetic sapphire containing the oxids of aluminum,iron and titanlum, having the same color transparency and hardness asthe natural sapphire, layers in its body portion, substantially as 10but distinguishable therefrom b havmg emdescribed.

bedded in its bodyportion an beneath its In testimony whereof, I aflixmy signasurfaised bubble like s (its boslmdedb gvith ture, in presenceof two witnesses.

roun e wa s su stantla as escri e 5. A synthetic sap phire d ontainingalumi- AUGUST}: VICTOR Lows VERNEUU" num, iron and titanium, havingbeneath its Witnesses: surfaces bubble like spots bounded with LomsRINUY, rounded walls, and also containing curved H. 0. 001m.

